Mr Karoshi

Man am I stuck on this! Using a Teensy 3 to communicate via serial to this fingerprint scanner, measuring 3.3V on it’s UART line (Serial 3) and getting absolutely nothing on the serial monitor in the Arduino software. Thinking it was a problem with level conversion I then tried using an 2N7000 MOSFET to prevent high levels damaging the scanner, still no response. The puzzling thing is I’m not sure if the scanner is expecting 0 - 5V TTL values or 0 - 3.3V TTL, and the same goes for the Teensy (although when it runs off of the USB connection I’d assume the Vref is 5v?). I’ve connected the pins as if the JST SH’s black wire is the Rx from the scanner, although they could be better colour co-ordinated! I’m completely stumped, any ideas guys??

Frontier Silicon have just released a module, referred to as the ‘Tuscany’, which supports Bluetooth, DAB, FM and USB docking which I am dying to get my hands on. Any chance it would surface here in the form of a breakout?

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